Keratoconjunctivitis sicca is an eye disease caused by eye dryness, which, in turn, is caused by inadequate quantity of tears or lower quality of tears in eyes. Severe eye dryness may cause pathologic changes to corneal epithelium. Usually, one eye of a person secret about 1 microliter (μl) of tears in one minute (1 μl/min). Decreased tear production or increased tear film evaporation may cause inadequate quantity of tears in eyes. As to the quality of the tears, tears with normal quality usually form a tear film over the eye surface. The tear film has three layers from outside to inside: oil layer, water layer, and mucous layer. Abnormality in any layer may cause the decrease in the quality of the tears.
Keratoconjunctivitis sicca is colloquially called dry eyes syndrome (DES). DES is usually characterized by abnormality in the quantity of tears, quality of tears, or kinetics of tears. The tear film becomes less stable. A patient may feel uncomfortable in eyes and/or have characteristic lesion on the external tissue of eyes. DES refers to a variety of diseases.
The common syndrome may include dry eyes, tiredness of eyes, sleepiness, itching eyes, sensation of foreign objectives in eyes, sensation of pain and burning in eyes, tight eyelids, thick eye secret, sensitivity to wind of eyes, sensitivity to light of eyes, sensitivity to external stimuli of eyes, and/or temporary blurring eyesight. If the eyes are too dry, the inadequacy of basal tears may stimulate the secretion of reflex tears. A patient may exhibit the symptom of tearing. A patient with severe DES may exhibit the syndrome of inflammation, hyperaemia, cornification, damages to corneal epithelium accompanied by adherence of filament material to the eyes. The chronic damages may cause pathologic changes of the cornea and conjunctiva and may affect eyesight.
For patients with keratitis at the palpebral fissure, the tear film may break in shortened time period, which may in turn cause keratitis filamentosa and/or keratoconjunctivitis sicca. The symptom may include reduction of the tear production at the palpebral fissure. Schirmer test may show the decreased tear production in patient. This disease usually appears to be an idiopathic disease among old people. The disease may also be commonly seen in patients with Sjogren's syndrome as a symptom expressed in eyes. Sjogren's syndrome may include dry mouth, dry eyes, and arthritis. The disease may also be commonly seen in patients with autoimmune diseases, and systematic diseases, such as sarcoma, and Waldenström's macroglobulinemia. The treatment methods may include artificial tears. Patients with severe symptoms may wear protective goggle or have the lacrimal puncta blocked.
For patients with the above mentioned symptoms, a physician may need to inquire the medical history to identify the cause. For patients with severe dry eye, a treating physician may need to inquire about other possible accompanying symptoms, such as dry mouth, or arthritis symptoms.
The DES symptoms may vary significantly among individual patient. Many patients complain about the sensation of foreign object in eyes, burning sensation or common uncomfortable feeling in eyes. These symptoms may be typically described as sensation of abrasion, dry eyes, pain, sensation of sand in the eyes, tingling sensation, or burning sensation. These discomforts are usually symptoms of DES, due to the fact that the surface of cornea is rich in sensory nerve endings. A significant portion of patients may be sensitive to light and have intermittent blurring eyesight or other eyesight problems. Clinically, DES constitutes a significant portion of eye disease.
Patients with DES often complain the tiredness of eyes, which cause difficulty reading and watching TV. The reason for these difficulties is that the frequency of winking is reduced when a patient concentrate on certain tasks. Normally, a person wink once for about every five (5) seconds. When the frequency of winking is reduced, the evaporation time of tear film is significantly extended. With inadequate winking, the cornea may be exposed for more than ten (10) seconds. One or more dry points may form on the surface of cornea. This occurs with relatively high ratio among young people. The average age of DES patients is reduced due to long time internet surfing, long time reading using mobile devices, and long term contact lens use among young generation.
Many DES patients may have both the decreased tear production and increased tear film evaporation. Before a treatment, a physician usually should identify the cause and take corresponding measures. DES is a chronic disease. Many patients need long term care. A physician may need to encourage a patient for long term treatment. Currently, lacrimal plug implantation has the advantage for providing long term adjuvant therapy. The plug may be removed by washing with normal saline solution. But the plug does not have regulating function. Patients with severe and mild symptom use the same type of plug. For some patient, tears may overflow and inflammation may follow. Other treatment includes closure of the lacrimal punctum using laser, which is a type of irreversible surgery.
Another treatment is fluid replacement therapy. The replacement therapy may include artificial tear replacement therapy and hormonal eyedrops. The artificial tear replacement therapy requires long term or even life time administration of the medicine. Further, the artificial tear and the additive therein may exacerbate the symptom. When a patient uses hormonal eyedrops, there is a risk that it would induce severe complication. The side effect is obvious.
The disclosed nasolacrimal plugs are directed at solving one or more problems set forth above and other problems.